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Biomedical subjects

S Algeri

Publications and source records attributed to S Algeri.

At least 91 records · Page 5Linked to original sources
PubMed1977

Effect of steroid contraceptive drug treatment on the catecholamine metabolism in the guinea pig central nervous system.

In an attempt to establish the biochemical basis of the neurological side-effects of steroid contraceptive drugs, the effect of chronic administration of lynestrenol-mestranol, a widely employed contraceptive combination, on the catecholaminergic system of the guinea pig striatum, brainstem, and hypothalamus, was investigated. The effect of these drugs on the transformation of tyrosine into dopamine and norepinephrine was investigated after cerobroventricular injection of a tracer dose of [3,5-3H]L-tyrosine. Treatment increased the conversion of [3H]Tyrosine into [3H]norepinephrine in the lower brainstem and hypothalamus was the same in treated and control animals. These findings confirm results previously obtained in female rats.

Animals↗
PubMed1976

Effect of anticholinergic drugs on gastro-intestinal absorption of L-dopa in rats and in man.

Plasma L-DOPA levels in rats receiving L-DOPA by the oral route were decreased by the concomitant administration of trihexyphenidyl. Following systemic L-DOPA administration no differences were observed between control and trihexyphenidyl-treated rats. Effects similar to those of trihexyphenidyl were observed with atropine. These results indicate that trihexyphenidyl decreases L-DOPA gastrointestinal absorption probably by delaying gastric emptying. The presence in humans of this interaction between the two antiparkinsonian drugs was suggested by similar findings made either in a group of normal volunteers or in a group of parkinsonian patients. These observations suggest that at the clinical level in selected cases the concomitant administration of trihexyphenidyl to patients receiving L-DOPA may decrease the therapeutic efficacy of L-DOPA by reducing its gastrointestinal absorption.

Administration, Oral↗
PubMed1976

Absence of relationships between L-dopa plasma levels and therapeutic effect in Parkinson's disease treated with L-dopa.

The plasma concentration of dopa was studied in 15 parkinsonian patients after a single administration of L-dopa. The study was undertaken in order to determine if correlation between plasma dopa concentration and clinical performance as a result of the tests carried out before and after a single dose of dopa, was present. Our data confirm the absolute absence of correlation between dopa levels in plasma and clinical improvement during long-term treatment. Moreover, clinical responses to the performance tests were not related to the concentration of circulating L-dopa in the plasma. Therefore dopa levels cannot be useful in clinical practice but only for the prevention of too high concentrations of plasma L-dopa which often cause a few side-effects.

Administration, Oral↗
PubMed1976

Biochemical effects of treatment with oral contraceptive steroids on the dopaminergic system of the rat.

The effects of acute and chronic administration of a combination of lynestrenol-mestrenol, a widely employed contraceptive medication, on the dopaminergic system of the rat forebrain and striatum were investigated to better understand the biochemical basis of the neurological side-effects of steroid contraceptive drugs (SCDs). Both acute and chronic treatment increased the disappearance rate of striatal dopamine (DA) after synthesis blockade with alpha-methyl-p-tyrosine (alpha-MpT). Moreover, the conversion of 3H-tyrosine (3H-T) into 3H-DA was increased in the forebrain and striatum after chronic administration of this steroid combination. In the same animals, the utilization of tyrosine (T) is increased.

Animals↗
PubMed1970

In vivo conversion of 3H-L-tryptophan into 3H-serotonin in brain areas of adrenalectomized rats.

Rats were adrenalectomized 10 days before we estimated in vivo the conversion index of (3)H-tryptophan into radioactive serotonin in brainstem and telediencephalon. We found that the conversion index in the brainstem of adrenalectomized rats is smaller than in the same area of sham-operated rats. Conversely, the conversion index in the telediencephalon was similar in the two groups of rats. The serotonin concentrations were unchanged by adrenalectomy, which suggests that in brainstem the decrease of tryptophan hydroxylase is reflected by the conversion index estimation and not by measurement of serotonin steady-state concentrations.

Adrenalectomy↗
PubMed1969

Lesions of central norepinephrine terminals with 6-OH-dopamine: biochemistry and fine structure.

Intracisternal injections of 6-hydroxydopamine produce rapid and long-lasting depletion of brain catecholamines without effects on serotonin concentrations. Depletion of norepinephrine is greatest in areas containing only nerve terminals and axons and least in areas containing monoamine cell bodies. The norepinephrine loss is accompanied by electron microscopic evidence of nerve terminal degeneration and decreased turnover. Dopamine loss is less marked and is not accompanied by degeneration or alteration of turnover rate.

Animals↗
PubMedDate not supplied

The ACTH/MSH (4-9) analog Org2766 improves retrieval of information after a fimbria fornix transection.

The fimbria fornix of male Wistar rats was transected unilaterally after they had been successfully trained in the Morris maze and the passive avoidance task. Sham-operated and lesioned animals were treated either with Org2766 or saline for two weeks. Subsequently, the performance of all groups was tested again starting two days after the last treatment. The lesioned animals showed a deficit in performance in both tasks, indicating interference of the lesion with retrieval of information. Org2766 improved the poor performance of the lesioned animals in the Morris maze, but not in the passive avoidance task.

Adrenocorticotropic Hormone↗